1. Field of the Invention
This invention relates to a novel dehydrogenative silylation process wherein a tert-butyldimethylsilyl is introduced into organic compounds.
2. Description of the Prior Art
In recent trends for the preparation of .beta.-lactam antibiotics or prostaglandins, an --NH group and/or --OH group are usually protected with a t-butyldimethylsilyl group. This is because the protective group is resistant to the Grignard reaction, the Wittig reaction, diisobutyl aluminum hydride reduction and the Jones oxidation but can be very readily eliminated by the attack of F ions (see T. N. Saltzman et al., J. Am. Chem. Soc. 102, 6161 (1980)).
Silylating agents conventionally used to protect active hydrogen with a t-butyldimethylsilyl group are a chlorosilane of the formula, (CH.sub.3).sub.3 CSi(CH.sub.3).sub.2 -Cl, without exception. The reason why this chlorosilane is utilized for this purpose is believed due to the fact that studies in this field have been made mainly by the Corey procedure (E. J. Corey et al, J. Am. Chem. Soc., 94, 6190 (1972)).
The use of the tert-butyldimethylchlorosilane has the following drawbacks: solid quaternary ammonium salts secondarily produced during the silylation reaction have to be removed; since the chlorosilane causes reactor materials, particularly iron, to be corroded, a glass-lined reactor must be used; and the t-butyldimethylchlorosilane is solid at room temperature and is rather difficult to handle.